Hubble factsheet

Name The Hubble Space Telescope (HST), or just ‘Hubble’, is named after Edwin Powell Hubble (1889–1953) who was one of the great pioneers of modern astronomy.

Description Hubble is a collaboration between ESA and NASA. It is a long-term, space-based observatory. The observations are carried out in visible, infrared, and ultraviolet light. In many ways, Hubble has revolutionised modern astronomy, not only as an efficient tool for making new discoveries, but also by driving astronomical research in general.

Journey Hubble was deployed by the Space Shuttle Discovery (STS-31) into a circular orbit 600 kilometres above the ground, inclined at 28.5 degrees to the Equator. The time for one orbit is about 96 minutes.

Notes An optical defect was discovered in the original Hubble mirror. Astronauts on board a later Space Shuttle flight restored the telescope. Brilliantly executed, the repair will go down in history as one of the highlights of human spaceflight.

Hubble’s orbit high above the Earth allows astronomers to make the very high resolution observations (without atmospheric distortion) that are essential to open new windows to planets, stars, and galaxies. Furthermore, access to infrared and ultraviolet light can only be achieved with a space telescope, because the atmosphere prevents it from reaching the ground.

Typically, more than 1000 proposals to use Hubble are received each year, of which some 250 are finally selected. It is a measure of Hubble's continuing relevance that this proportion is so high.

European scientists are guaranteed access to 15% of Hubble observing time. In recent years, the fraction of allocated time to European scientists has been about 20%, which is not only a reflection of Europe's contribution to the project but also the quality of the European proposals.